Recently developed optical-resolution photoacoustic microscopy (OR-PAM), which is based on the detection of optical absorption contrast, is complementary to other optical microscopy modalities such as optical confocal microscopy, optical coherence tomography, and multiphoton microscopy. A hybrid optical–mechanical scanning configuration increases the imaging speed of OR-PAM significantly, facilitating many demanding biomedical applications. With a high-pulse-repetition-rate laser, the hybrid-scanning OR-PAM can acquire one-dimensional depth-resolved images (A-lines) at $5\mathrm{kHz}$ and two-dimensional B-scan images containing 800 A-lines at $6.25\mathrm{Hz}$ . We demonstrated in vivo in a mouse three-dimensional imaging of the iris vasculature in $128\mathrm{s}$ for an $800\times 800\times 200$ data set and of the ear vasculature in $256\mathrm{s}$ for an $800\times 1600\times 200$ data set.